A wide variety of materials are stacked on wood pallets. Both pallets and the material stacked on them can be easily moved with a fork-lift or other standard handling equipment. Once the material on the pallet has been removed, the pallet remains. Generally pallets are not reused and as a result present a disposal problem for the owner. State and local fire and pollution laws prevent disposal by burning while most trash removal services will not accept used pallets. More often then not the pallets are simply stacked outside of buildings where they become a nuisance, safety hazard and eyesore.
Various devices have been developed for shredding various materials. However, none of these devices provide a mobile, highway travelable machine that uses a single power source for both locomotion and shredder operation. None of these devices suggests a single-drive machine that can be driven to the site of the pallets, shred the pallets, and then driven away with the shredded material.
Examples of the prior art include U.S. Pat. No. 3,752,409 to Lewis, Aug. 14, 1973 that describes a railroad tie shredder mounted on a flat bed railroad car. The invention has a crane for picking up uniform-size ties and placing them on a conveyor which advances them into a cutting and punching mechanism. The resulting fragments are discharged along the railroad bed by means of a blower. This invention uses a diesel engine to drive the shredder and a hydraulic motor to power the railroad car upon which the shredder is mounted. The diesel motor unit is designed primarily for use with the shredder, i.e., the cutting and punching mechanism. Because of the reliance on a hydraulic motor, the railroad car itself can travel at only two speeds, a fast speed of about 25 mile per hour and a slow creeper speed of about 1 to 10 miles per hour. Because of these slow travel speeds, this device is not functional as a highway vehicle. Furthermore, the machine is designed with little consideration for the length, width, and weight limitations imposed on users of the highway system. A vehicle of the type described in the Lewis patent would simply not be allowed on the highways because of its immense size and weight. Moreover the Lewis machine discharges the shredded wood product on the ground along the railroad bed, a practice that would hardly be allowed by the private land owners along our highway systems and has little relevance when one considers that pallet shredding is done on site and not along the roadway. To simply discharge the shredded wood product on the ground at the site of the pallets would simply trade one problem for another, i.e,, it would replace a pile of pallets with a pile of wood chips.
Furthermore, unlike multi-sized pallets, railroad ties are of uniform size enabling the use of specifically designed conveyors, cutters, and lifting equipment for a specific material. Pallets come in multiple sizes and shapes and therefor require a different design for handling.
U.S. Pat. No. 3,929,294 to Cox, Dec. 30, 1975, discloses a device for reducing scrap lumber and waste forest products found along the roadway into uniform short lengths. The wood breaker is powered by a motor which is separate and distinct from the power source used to transport the invention to the work site. Furthermore, the shredded product from the Cox invention is conveyed to a separate transporting truck for hauling; the wood to be shredded must be loaded with separate equipment such as a shovel loader or similar equipment.
U.S. Pat. No. 4,390,132 to Hutson et al., June 28, 1983 describes a wood chipper for reducing trees to wood chips. This invention uses a separate engine to drive the chipping mechanism and is transported to the work site by means of a vehicle with its own motor. A separate truck is used to remove the reduced wood chips.
French Demande No. 2,312,599 to Lager Jan. 28, 1977 discloses a machine for chopping wood from discarded pallets or packing cases into small pieces and removing the iron from the pieces in order that the shredded wood maybe used for paper making. The invention is placed on a trailer bed for towing by a truck and uses a separate self-contained engine for driving the pulverizing apparatus.
U.S. Pat. No. 3,189,286 to O'Connor, June 15, 1965, reveals a paper shredding apparatus in which the engine for driving the apparatus is separate and distinct from the engine used to convey the apparatus from location to location. The size of such an apparatus and the power source to operate it are not comparable to the size of the power source required to shred wooden pallets.
U.S. Pat. No. 3,913,850, to Daniel, Oct. 21, 1975, reveals a mobile tire shredder in which the motor for shredding the tires is separate and distinct from the engine used to drive the vehicle.
As is apparent from the prior art, previous inventors have used a separate power source to operate mobile shredder devices. Even U.S. Pat. No. 3,752,409 uses a diesel engine to drive the shredder and an auxiliary hydraulic motor to drive the railroad car.
A separate shredder drive engine is used because the engine used to move the vehicle on which the shredding apparatus is mounted is not suited for operating the shredding apparatus. Typically an engine used to move the shredder vehicle on the highway operates at relatively high speeds without substantial loading being placed upon the engine. If such an engine were hooked to a shredding machine, the large load and torsional resistance of the large pieces of wood as they are being shredded would place such great stress and strain on the vehicle engine and its associated transmission that such engine and transmission would be rendered inoperable within a very short period.
Although stationary wood shredders are known, they are not designed for mobile use. A typical stationary shredder is securely mounted on a concrete pad and is often over fifteen feet tall. Because of height requirements placed on highway users, such shredders are not capable of being mounted on a truck chassis. Furthermore, the vibrational and torsional drive shaft stress produced by a stationary shredder do not allow for direct connection to a vehicle motor and transmission.